AbstractFractal development during polymerization of a dimethacrylate system (Bis‐GMA/TEGDMA) has been studied through the analysis of time series obtained sequentially by pulsed photoacoustics. The photoacoustic signals as obtained in situ during photopolymerization of Bis‐GMA/TEDGMA were analyzed by rescaled range analysis, dispersion analysis, and detrended fluctuation analysis methods. The analysis reveals the presence of more than one scaling parameter and, therefore, belongs to a complex process known as multifractal. The evolution of fractality during photopolymerization was compared under equivalent conditions with the chemical conversion (of dimethacrylate double bonds) as a function of time, as monitor by infrared spectroscopy. This kinetic study was also used to correlate the fractal nature of the dimethacrylate reaction system with the condensed‐state transitions emerging during the photochemical reaction. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009